Thermoelasticity and the temperature coefficient of unperturbed polymer dimensions

Abstract

The strain dependence of fe/f (ratio of the internal energy component of the force to the total retractive force) for a crosslinked, amorphous network is analyzed in t e r m of the C, factor which appears in the semi-empirical relation for rubber elasticity. Appropriate equations are derived and applied to literature data for several polymers and copolymers. The temperature coefficients of the mean-square end-to-end distances thus obtained are often quite different from the values determined by averaging fe/fT a t several extensions. ZUSAMMENFASSUNG:Die Spannungsabhangigkeit von fe/f (Verhdtnis des Anteils der Kraft aus der inneren Energie zu der gesamten riicktreibenden Kraft) eines verzweigten amorphen Netzwerkes w k d e untersucht nnd mit Hilfe des C&-Faktors, der in der halbempirischen Beziehnng fur die Kautschukelastizitat auftritt, beschrieben. Es wurden naherungsweise giiltige Gleichungen abgeleitet und auf die fiir einige Polymere und Copolvmere aus der Literatur bekannten Daten angewandt. Die so erhaltenen Temperaturkoeffizienten des mittleren Quadrates des Fadenendenabstandes sind oft erheblich von den Werten verschieden, die aus dem Durchschnitt von fe/fT bei verschiedenen Dehnungen erhalten wurden.

Configurational properties of polyesters derived from aliphatic diacids and 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane

“…The step condensation reactions were conducted in refluxing toluene solutions, utilizing a high concentration of reactants (~50% w/w), with the aim of avoiding the formation of high molecular weight cycles. 10 The reaction time was 24 h, and the water formed during the reaction was separated by means of a Dean-Stark distillation trap. In the final steps of the reaction a slight excess of dyanol-22 was added to the reaction medium, with the aim of obtaining hydroxyl-terminated chains, and the reaction was permitted to proceed for another 5 h. The polyesters were precipitated with n-hexane, and then they were washed several times with water in order to eliminate the catalyst.…”

Thermoelastic properties of networks in swelling equilibrium: Poly(vinyl alcohol)

“…We have recently generalized this result and obtained the following results valid for one component diluent~:~ ( V J V ) _N a -1 / 2 (7) P e = 5PJ6 (8) where PS = (b In V,/bT),,,. Equations (7) and (8) depend upon the validity of Flory-Huggins solution theory as well as the kinetic theory of elasticity.…”

Thermoelastic Behavior of Rubber-Like Materials at Large Deformations

“…We rewrite these constants as (11) which was first introduced by Blatz. s Under the constraints of constant volume and length, its temperature coefficient is just…”